Process of disinfecting hides and skins in the manufacture of leather.



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No Drawing.

To all whom it may concern Be it'known that I, OTTO Rona, a subject of the Emperor of Germany, residing in Darmstadt, Germany, have invented certain new and useful Improvements in the Process of Disinfecting Hides and Skins in the Manufacture of Leather, of which the following is a specification.

My invention relates to improvements in the process of disinfecting hides and skins in the manufacture of leather and it has for its object to provide a process of treatment which will effect the preservation thereof by the elimination of bacteria therefrom and without injury to the hides or skins due to any action of the material used in the practising of the process. u

For a long time it has been the endeavor of those engaged or interested in the tanning of leather to eliminate as far as possible the presence of bacteria in hides and skins during the process of such manufacture prior to the subjection of the hides and skins to the tanning materials and thus prevent injury to such hides and skins. Disinfectants of various kinds have been suggested for use in the treating of hides and skins to disinfect them but for one reason or another such disinfectants have been objectionable and their use impracticable.

I have discovered that by the treatment of hides and skins with a solution of copper salts containing the copper in such form that it cannot be precipitated by the h'ydroxid of an alkali metal they are disinfected and protected against injurious bacterial action. This result is obtained without injury to the hides or skins due to some action of the disinfectant upon the fibers thereof.

As instances of copper salts which may be employed in my process I mention copperammonium salts and soluble complex copper salts such as glycocollcopper, coppertartrate and similar complex copper salts. It has been discovered that these complex copper salts have no tanning action upon the hides o'r skins and in that respect they are analogous to the complex chrome salts. As these complex copper salts have no tanning action and are not precipitated on the fibers of the hides or skins they can be washed out completely and easily before the hides or skins are transferred to the tanning liquor to be tanned. This is a great advantage which pee fleati o attes Ret Pat d J an- 6,

A pplication filed December 4, 1911 Serial No. (563,902.

could not have been foreseen for if the coper salts were to remain in any considerable quantity upon the hides or skins there would appear a disturbing and an objectionable change of colors in case the leather should be dyed with wood colors which are known as mordant dyes.

In the employment of my invention the hides and skins are treated with a solution of complex copper salts, such as above set forth, at any time prior to the time that such hides and skinsare placed the taIi ning liquor. The said hides or skins should be washed before being placed in the tanning liquor for the purpose of removing the copper salts.

The process of treating hides and skins according to my invention may be employed to great advantage during the bating thereof for the purpose of keeping out the micro-organisms or bacteria. It has been found that complex copper salts such as have been referred to above may be employed during the hating process because they do not destroy the enzyms which are essential for the purpose of securing a proper hating efiect and because also when such copper salts are used in reasonable concentration they do not affect the action of the enzyms in any way. Consequently they may be used to free the hating liquor from bacteria and thus eliminate the danger of damage which may be imminent from the presence of such bacteria. The process of treating the hides and skins with a solution of complex copper salts, as hereinbe' fore set forth, can also be employed to advantage at other periods in the process of manufacturing leather. For instance, the hides or skins may be protected from the action of bacteria during the process of soaking or during the time between the liming and hating or between the latter process and the time that the hides or skins are placed in the tanning liquor. I have also discovered that during the time raw hides are in course of transportation from one point to another or during the time that such hides are stored, they may be sterilized and protected against the action of bacteria by subjecting them to the action of a concentrated solution of common salt (NaCl) to which a small quantity of complex copper salts has been added. After having been treated with such solution of common salt and complex copper salts the hides are allowed to drain oil and to dry.

Having thus described my invention, I claim 1. The process of disinfecting hides and skins Which consists in treating the same with a solution of a copper salt containing the copper in such form that it cannot be precipitated by the hydroxid of an alkali metal to thereby prevent the action of bacteria on such hides or skins.

2. The process of disinfecting hides and skins during the process of manufacturing leather prior to the placing of the same in the tanning liquor, which consists in applying thereto a solution of a copper salt containing the copper in such form that it cannot be precipitated by the hydroxid of an alkali metal.

3. The process of treating hides during the process of manufacturing leather prior to the placing of such hides and skins in a tanning liquor, which consists in treating the same, for the purpose stated, With a solution of copper salt simultaneously with the bating of the same, such salt containing the copper in such form that it cannot be precipitated by the hydroxid of an alkali metal.

4. The process of treating hides and skins to destroy bacteria thereon which consists in treating the same With an alkaline solution of copper salt.

5. The process of'treating hides for the purpose of sterilizing and disinfecting the same which consists in treating the same With a concentrated solution of common salt to which a small quantity of a copper salt containing the copper in such form that it cannot be precipitated by the hydroxid of an alkali metal has been added.

In testimony that I claim the foregoing as my invention, I have hereunto signed my name this 12. day of November, A. D. 1911,

at Darmstadt, Germany.

OTTO ROHM.

In the presence of MAX GoLnMANN, RICHARD KAUTTER.

Cdpies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. C. 

